Beyond Factory: A BMW M340i with Porsche GT3 Calipers & STOPFLEX Carbon-Ceramics
The BMW M340i is the undisputed heavy hitter of the 3-Series lineup, the "first lieutenant to M-Power." Its B58 inline-six is famously underrated, and with a simple tune, owners are pushing well past 400 horsepower. But as every serious driver knows, adding that much "go" exposes the limits of the factory "stop." For high-performance driving, the stock brakes are simply the weak link.
The Pro-Level Upgrade Plan
When "good enough" isn't an option, you look to the absolute best. For this tuned M340i, the owner chose a front-axle setup that blends motorsport pedigree with cutting-edge material science—a combination engineered for devastating performance:
Front Axle: A legendary set of Porsche GT3 6-Piston Calipers paired with our STOPFLEX 410mm (16.1 in) Carbon-Ceramic Discs. The system is completed with our proprietary STOPFLEX Performance Pads formulated specifically for carbon-ceramic rotors.
Fitment Requirements for STOPFLEX Rotors
Our carbon-ceramic systems are designed for serious builds. This M340i's custom setup is a perfect match for our engineering criteria:
Caliper Type: The Porsche GT3 caliper is a motorsport-grade opposed 6-piston (fixed) design, providing the immense and evenly-distributed clamping force our rotors are designed to handle.
Minimum Size: The massive 410mm disc provides the thermal capacity required for a high-powered sedan, easily exceeding our 355mm minimum.
The Result: A Complete Transformation
Motorsport-Grade Stopping Power. The Porsche GT3 caliper is an icon for a reason: its rigidity and power are proven on the world's toughest tracks. But a caliper is only as good as the rotor it squeezes. Our 410mm carbon-ceramic disc provides the thermal stability to absorb that punishment, lap after lap, stop after stop, without a hint of fade. This isn't just an upgrade; it's a total re-engineering of the car's braking limits.
Sharper Handling, Quicker Response. The most immediate benefit after raw power is the massive weight reduction. A STOPFLEX carbon-ceramic disc is up to 50% lighter than its iron equivalent. By slashing that much unsprung mass from the front axle, the M340i's already excellent suspension can react faster. The result is a car that turns in more sharply, feels more planted over rough surfaces, and is simply more agile and responsive to driver input.
Refinement for the Daily Drive. Ultimate performance shouldn't require compromise. This system delivers a premium experience on the street with silent, smooth operation. And for owners who value aesthetics as much as performance, our system produces virtually zero brake dust. The aggressive look of the GT3 caliper and carbon rotor now stays clean, preserving the car's sharp looks without constant wheel cleaning.
Installation Gallery
Questions About This Build
Q: Why use Porsche calipers on a BMW?
A: It's about using the best tool for the job. Porsche's track-focused brake development is legendary. For enthusiasts creating a custom build, adapting a proven, motorsport-grade caliper like the GT3's offers a level of performance and durability that few others can match. Our engineered rotor hats and brackets make this pro-level integration a bolt-on affair.
Q: Is a 410mm carbon-ceramic system overkill for a street car?
A: For a stock car, maybe. For a tuned M340i that's driven enthusiastically, it's about creating an unbreakable thermal safety net. You'll never experience brake fade on a backroad or during a track day. Plus, the significant reduction in unsprung weight improves ride quality and handling everywhere—not just at the limit.